In the current work, the behavior of double phase martensite-ferrite steel has been studied based on the parametric study of micromechanical specifications on the morphology of double phase steel. It seems that the microstructures of steel have important effects on DP Steel's behavior. In the current study, it is assumed that there is a grain boundary between ferrite and martensite and the behavior of ferrite and martensite is elastoplastic. In this work, the finite element method has been used. At first, the effect of martensite particles layout on the soft ferrite domain has been investigated. Martensite particles are positioned in the sample volume in two different forms (regular and irregular) and the strain-stress figures have been plotted. At the second step of this work focuses on the effect of volume fraction of martensite particles (0.13,0.18,0.25) in both layouts (regular and irregular) Therefore, the area of martensite in both cases are equal and only the number of these particles in each volume fraction is calculated and applied in the model. The aspect ratio of martensite grain next, an RVE contains martensite grains with an aspect ratio of greater than one was considered ones all particles aspect ratio in the model was assumed to be constant while in another model martensite grains with different aspect ratio was considered. In modeling the effect of martensite particles, the surfaces area of martensite particles is equal and only the ratio of the large oval diameter on the short oval diameter in martensite particles changes. Finally, the effect of increasing the diameter of martensite particles (in the regular and irregular form) is investigated. It can be seen that the layout of martensite particles has significant effects on the microstructure properties. The results indicate that plastic strain distribution is more uniform the regular structures than the irregular ones. It means that although the regular structure is better than the irregular ones, in irregular samples, the more regular martensite islands lead to less damage in the sample. Also, the simulation of the effect of stretching the particles shows that the stretched and connected martensite phase increases the stretch. Keywords: Dual phase steel, Stretch of martensite particles, Effect of particle size, Mechanical properties of dual phase steel